Which type of metamorphosis includes stages of egg, naiad, and adult?

The type of metamorphosis that includes the stages of egg, naiad, and adult is known as incomplete metamorphosis. In insects exhibiting this type of development, the life cycle consists of three stages: the egg, the nymph (or naiad when referring to aquatic species), and the adult.

The naiad is an immature form that lives in a habitat suitable for growth and sometimes bears a resemblance to the adult but is typically smaller and lacks fully developed wings, which are present in the adult form. This process allows for a gradual transition between life stages, as naiads often undergo several molts before becoming fully developed adults.

In contrast, complete metamorphosis involves a four-stage life cycle (egg, larva, pupa, and adult) and requires distinct transformations that separate the larval and adult forms significantly. The option for no metamorphosis is not applicable to the context of this question, as all organisms undergo some form of change during their life cycles. Gradual metamorphosis, while similar to incomplete metamorphosis, typically involves nymphal stages that more closely resemble adults throughout development. Incomplete metamorphosis explicitly includes the naiad stage, making it the correct answer.